I feel like each update the game feels like a different game genre.
- Update 1: Infiltration/stealth shooter.
- Traveling bullets.
- No dogs.
- Free exploration of the map.
- Update 2: Boomer shooter.
- High damage output.
- High rate of fire and quick reloading.
- Dogs.
- Many enemies (including dogs).
- Update 3: Tactical/strategic shooter.
- Low damage output.
- Slow reloading shotgun.
- Limited supplies.
- Supplies are "high risk, high reward" due to its location.
- Few enemies.
- Higher difficulty the deeper you get.
Each of these updates are fun on their own, and some people may prefer one over another, why not put a menu at the start to select the mode of play (Infiltration, Assault, Heroic)?
Depending of the gamemode the player selects the game changes the stats (damage, enemy health, reload time, bullet travel...) and the location of the objects (enemies and supplies).
You may also put crates on the map to create covers to hide in, shortcuts to ambush and highgrounds to locate enemies and shoot'em. The position of these crates can change depending of the gamemode.
This may be hard to implement (the crate thing isn't the main focus of my suggestion) but I think that it would be really cool a game whose premise is "X genres on 1 game" sort of thing.
